scholarly journals Phase Stability and Transport Properties of (ZrO2)0.91−x(Sc2O3)0.09(Yb2O3)x Crystals (x = 0–0.01)

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 83
Author(s):  
Mikhail Borik ◽  
Galina Korableva ◽  
Alexey Kulebyakin ◽  
Irina Kuritsyna ◽  
Nataliya Larina ◽  
...  
Keyword(s):  
High Temperature ◽  
Transport Properties ◽  
Phase Stability ◽  
Rf Heating ◽  
X Ray Diffraction ◽  
High Temperature Heat Treatment ◽  
Before And After ◽  
T Phase ◽  
High Phase

Phase stability and transport properties of (ZrO2)0.91−x(Sc2O3)0.09(Yb2O3)x crystals (x = 0–0.01) have been studied before and after air annealing at 1000 °C for 400 h. The crystals have been grown by radio frequency (RF) heating in a cold crucible. The microstructure, phase composition, and electrical conductivity of the crystals have been studied using optical microscopy, X-ray diffraction, Raman spectroscopy, and impedance spectroscopy. Phase stability and degradation of ionic conductivity of the crystals upon long-term high-temperature heat treatment have been discussed. We show that the stabilization of ZrO2 co-doped with 9 mol.% Sc2O3 and 1 mol.% Yb2O3 provides transparent uniform crystals with the pseudocubic t″ phase structure having high phase stability. Crystals of this composition had the highest conductivity in the entire temperature range. Long-term high-temperature annealing of these crystals did not lead to conductivity degradation.

scholarly journals Novel Multilayer SAW Temperature Sensor for Ultra-High Temperature Environments

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 643
Author(s):  
Xuhang Zhou ◽  
Qiulin Tan ◽  
Xiaorui Liang ◽  
Baimao Lin ◽  
Tao Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Sensor ◽  
X Ray Diffraction ◽  
Aero Engine ◽  
Before And After ◽  
Application Potential ◽  
Passive Sensors ◽  
Temperature Exposure ◽  
Engine Systems

Performing high-temperature measurements on the rotating parts of aero-engine systems requires wireless passive sensors. Surface acoustic wave (SAW) sensors can measure high temperatures wirelessly, making them ideal for extreme situations where wired sensors are not applicable. This study reports a new SAW temperature sensor based on a langasite (LGS) substrate that can perform measurements in environments with temperatures as high as 1300 °C. The Pt electrode and LGS substrate were protected by an AlN passivation layer deposited via a pulsed laser, thereby improving the crystallization quality of the Pt film, with the function and stability of the SAW device guaranteed at 1100 °C. The linear relationship between the resonant frequency and temperature is verified by various high-temperature radio-frequency (RF) tests. Changes in sample microstructure before and after high-temperature exposure are analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis confirms that the proposed AlN/Pt/Cr thin-film electrode has great application potential in high-temperature SAW sensors.

scholarly journals Low-Power Laser Graphitization of High Pressure—High Temperature Nanodiamond Films

2020 ◽  
Vol 10 (9) ◽  
pp. 3329
Author(s):  
Konstantin G. Mikheev ◽  
Tatyana N. Mogileva ◽  
Arseniy E. Fateev ◽  
Nicholas A. Nunn ◽  
Olga A. Shenderova ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Laser Excitation ◽  
X Ray Diffraction ◽  
Power Laser ◽  
Green Luminescence ◽  
X Ray ◽  
Atomic Force ◽  
High Pressure High Temperature ◽  
Before And After

Laser-induced graphitization of 100 nm monocrystals of diamond particles synthesized by high-pressure high-temperature (HP-HT) methods is not typically observed. The current study demonstrates the graphitization of 150 nm HP-HT nanodiamond particles in ca. 20-μm-thick thin films formed on a glass substrate when the intensity of a focused 633 nm He-Ne laser exceeds a threshold of ~ 33 kW/cm2. Graphitization is accompanied by green luminescence. The structure and morphology of the samples were investigated before and after laser excitation while using X-ray diffraction (XRD), Raman spectroscopy, atomic force (AFM), and scanning electron microscopy (SEM). These observations are explained by photoionization of [Ni-N]- and [N]-centers, leading to the excitation of electrons to the conduction band of the HP-HT nanodiamond films and an increase of the local temperature of the sample, causing the transformation of sp3 HP-HT nanodiamonds to sp2-carbon.

scholarly journals Long-term entrapment and temperature-controlled-release of SF6 gas in metal–organic frameworks (MOFs)

2019 ◽  
Vol 10 ◽  
pp. 1851-1859 ◽  
Author(s):  
Hana Bunzen ◽  
Andreas Kalytta-Mewes ◽  
Leo van Wüllen ◽  
Dirk Volkmer
Keyword(s):  
Elevated Temperature ◽  
Metal Organic Framework ◽  
Gas Pressure ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Before And After ◽  
Metal Organic ◽  
Gas Molecules ◽  
Zinc Cations

In this work, a metal–organic framework (MOF), namely MFU-4, which is comprised of zinc cations and benzotriazolate ligands, was used to entrap SF6 gas molecules inside its pores, and thus a new scheme for long-term leakproof storage of dangerous gasses is demonstrated. The SF6 gas was introduced into the pores at an elevated gas pressure and temperature. Upon cooling down and release of the gas pressure, we discovered that the gas was well-trapped inside the pores and did not leak out – not even after two months of exposure to air at room temperature. The material was thoroughly analyzed before and after the loading as well as after given periods of time (1, 3, 7, 14 or 60 days) after the loading. The studies included powder X-ray diffraction measurements, thermogravimetric analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, 19F nuclear magnetic resonance spectroscopy and computational simulations. In addition, the possibility to release the gas guest by applying elevated temperature, vacuum and acid-induced framework decomposition was also investigated. The controlled gas release using elevated temperature has the additional benefit that the host MOF can be reused for further gas capture cycles.

scholarly journals The Effect of Simultaneous Si and Ti/Mo Alloying on High-Temperature Strength of Fe3Al-Based Iron Aluminides

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4268
Author(s):  
Věra Vodičková ◽  
Martin Švec ◽  
Pavel Hanus ◽  
Pavel Novák ◽  
Antonín Záděra ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Yield Stress ◽  
Electron Backscatter Diffraction ◽  
Xrd Analysis ◽  
Iron Aluminides ◽  
High Temperature Strength ◽  
X Ray Diffraction ◽  
Backscatter Diffraction

The effect of phase composition and morphology on high-temperature strength in the compression of Fe-Al-Si-based iron aluminides manufactured by casting was investigated. The structure and high-temperature strength in the compression of three alloys—Fe28Al5Si, Fe28Al5Si2Mo, and Fe28Al5Si2Ti—were studied. Long-term (at 800 °C for 100 h) annealing was performed for the achievement of structural stability. The phase composition and grain size of alloys were primarily described by means of scanning electron microscopy equipped with energy dispersive analysis and Electron Backscatter Diffraction (EBSD). The phase composition was verified by X-ray diffraction (XRD) analysis. The effect of Mo and Ti addition as well as the effect of long-term annealing on high-temperature yield stress in compression were investigated. Both additives—Mo and Ti—affected the yield stress values positively. Long-term annealing of Fe28Al5Si-X iron aluminide alloyed with Mo and Ti deteriorates yield stress values slightly due to grain coarsening.

Phase relations and superconducting properties of the Y–Ni–B–C system

1999 ◽  
Vol 14 (1) ◽  
pp. 16-23 ◽  
Author(s):  
G. Behr ◽  
W. Löser ◽  
G. Graw ◽  
K. Nenkov ◽  
U. Krämer ◽  
...  
Keyword(s):  
High Temperature ◽  
Intermetallic Phase ◽  
Phase Relations ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Residual Resistance ◽  
High Temperature Heat Treatment ◽  
Temperature Heat ◽  
Temperature Heat Treatment

The influence of composition and high-temperature heat treatment on phase content and superconducting properties of the Yni2B2C phase was investigated. Phase relations in those parts of the Y–Ni–B–C quaternary phase diagram, which are relevant for the YNi2B2C intermetallic phase formation, were revealed by x-ray diffraction, optical and scanning electron microscopy, and high-temperature differential thermoanalysis. A widespread interval of superconducting transition temperatures TC = 10.4–15.2 K and small transition width <0.3 K were determined from samples of different nominal compositions after high-temperature annealing. The different intrinsic properties are ascribed to composition variations of the YNi2B2C phase and related to structure parameters, residual resistance ratios, and element concentrations determined by the electron probe microanalysis.

Effect of Long-Term Ageing at 600 °C on Microstructure of ZG1Cr10MoWVNbN Martensitic Heat-Resistant Steel

2018 ◽  
Vol 37 (6) ◽  
pp. 539-544
Author(s):  
Chengzhi Zhao ◽  
Ning Li ◽  
Yihan Zhao ◽  
Hexin Zhang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
M23c6 Carbide ◽  
Resistant Steel ◽  
Steam Turbines ◽  
Heat Resistant Steel ◽  
Property Variation ◽  
Heat Resistant ◽  
Before And After

AbstractA new kind of martensitic ZG1Cr10MoWVNbN heat-resistant steel has been attracted more attentions in recent years, which is mainly applied in ultra-supercritical steam turbines. The ageing property for ZG1Cr10MoWVNbN heat-resistant steel is very important because it often serves for long-time at high-temperature environment. Herein, a long-term ageing heat treatment was conducted on ZG1Cr10MoWVNbN steel at 600 °C heat for 17,000 hours. The microstructure evolution and property variation of the ZG1Cr10MoWVNbN steel were analysed before and after ageing, and also the effect of the precipitates on the mechanical properties was studied. The result showed that strength, the plastic index and impact power of the ZG1Cr10MoWVNbN steel were gradually decreased after long-term and high-temperature ageing at 600 °C due to the changes of martensite morphology and the coarsening of M23C6 carbide precipitation phase. Furthermore, fine precipitation of matrix MX carbide can also attribute to the change of mechanical properties at high temperature.

Evaluation on Microstructure Stability and Thermal Resistant Ability at High Temperature of Ternary-Blended Geopolymer

2021 ◽  
Vol 321 ◽  
pp. 73-79
Author(s):  
Hoc Thang Nguyen
Keyword(s):  
High Temperature ◽  
Rice Husk Ash ◽  
High Thermal Stability ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure Stability ◽  
Before And After ◽  
Materials Used

Stability of microstructure and heat resistant ability at high temperature is one of the important properties in ceramics or silicate materials which are normally exposed with fire such as refractories and insulation or other materials used in furnaces. This study used a ternary-blended geopolymer which was synthesized from an optimized mixture of red mud (RM), rice husk ash (RHA), diatomaceous earth (DE), and water glass solution (WGS) with silica modulus of 2.5. The geopolymer samples were tested thermal properties of heat resistance (%), volumetric shrinkage (%), mass loss (%) at 1000°C to evaluate thermal resistant ability. Changes of microstructure of the ternary-blended geopolymer samples were also characterized before and after exposed at high temperature using methods of X-ray diffraction (XRD), Thermogravimetric analysis or thermal gravimetric analysis (DTA-TGA), and Scanning electron microscope (SEM). The experimental results showed the ternary-blended geopolymer has high thermal stability and unchanged microstructure even at high temperatures. Hence, the geopolymer in this study is suggested to apply as an insolation with the upper limit of temperature to work at 1000°C.

Measurement of Long Range Order in the γ’ Phase of Nickel-Base Superalloys

1969 ◽  
Vol 13 ◽  
pp. 598-608
Author(s):  
J.R. Mihalisin
Keyword(s):  
High Temperature ◽  
Long Range ◽  
Range Order ◽  
Long Range Order ◽  
X Ray Diffraction ◽  
High Temperature Heat Treatment ◽  
Heat Treated ◽  
Temperature Heat ◽  
Long Time ◽  
Nickel Base

The long range order parameter (S) has been measured at room- temperature on the γ’ phase extracted from IN-731 and alloys 713C and 713LC by x-ray diffraction techniques. Measurements were obtained from specimens of IN-731 and alloy 713LC in the as-cast condition and after long time rupture testing. The alloy 713 c specimens were in the as-cast and high temperature heat treated conditions.It was found that long range order in the γ’ phase of IN-731 and alloy 713LC was changed very little after long time rupture testing, and after high temperature heat treatment in the case of alloy 713C.

The PZT system (PbTixZr1−xO3, 0≤x≤1.0): High temperature X-ray diffraction studies. Complete x-T phase diagram of real solid solutions (Part 3)

2013 ◽  
Vol 39 (3) ◽  
pp. 2889-2901 ◽  
Author(s):  
I.N. Andryushina ◽  
L.A. Reznichenko ◽  
L.A. Shilkina ◽  
K.P. Andryushin ◽  
S.I. Dudkina
Keyword(s):  
Phase Diagram ◽  
High Temperature ◽  
Solid Solutions ◽  
X Ray Diffraction ◽  
X Ray ◽  
T Phase ◽  
Real Solid

A new ordered phase in Mn-Al-C alloys

1983 ◽  
Vol 41 ◽  
pp. 252-253
Author(s):  
J. S. Gau
Keyword(s):  
High Temperature ◽  
Processing Technique ◽  
Rapid Quenching ◽  
X Ray Diffraction ◽  
Dendrite Morphology ◽  
Alloy Chemistry ◽  
Ε Phase ◽  
Stage Process ◽  
Convergent Beam ◽  
T Phase

Convergent beam electron diffraction (CBED) coupled with conventional diffraction studies is used to identify a new ordered phase in the Mn-Al-C ribbons produced by the melt extraction rapid quenching processing (RSP).Recently, developments in alloy chemistry and processing technique have made Mn-Al- C alloys a promising substitute for the Alnico magnets which dominate the permanent magnet market. The ferromagnetic T phase is formed through a two-stage process; from the high temperature disordered hexagonal ε phase, an ordered orthorhombic ε' phase is formed which is further shear transformed to the tetragonal ordered τ phase (L1o). The present investigation is to study the phase in the ribbons produced by the rapid liquid quenching process with a rotating copper disc at a cooling rate of about 105-9°C/sec. The ribbons have an average thickness of 50μm and are between 2mm to 40mm in length. The as cast structure exhibits a dendrite morphology with an average arm spacing of l.0μm. X-ray diffraction examination of the cast ribbons reveals that the material is quenched into the high temperature disordered ε phase.

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